What is being tested?
Measles (rubeola) and mumps are viruses that are members of the Paramyxoviridae family. They both cause infections that usually resolve within several days but can sometimes cause serious complications in certain cases. Both are preventable through vaccination.
Measles and mumps testing may include:
- Testing for antibodies in the blood that develop in response to measles or mumps infection
- Testing for viral genetic material (RNA) in a sample using a molecular method such as polymerase chain reaction (PCR). This method may be used for a variety of samples.
The number of cases of measles and mumps infections in the U.S. has decreased because most people have received the MMR vaccine that protects against measles, mumps, and rubella. In recent years, the majority of new cases in the U.S. have occurred in occasional outbreaks (epidemics), primarily in people who have not been vaccinated, especially those who have traveled to areas of the world where measles or mumps are more prevalent.
Measles, also called rubeola, is a virus that infects cells in the lungs and the back of the throat. It is an extremely contagious viral infection that is easily spread through coughing and sneezing or touching a surface contaminated with the virus and then touching your mouth, nose or eyes. According to the Centers for disease control and Prevention (CDC), the measles virus can live for up to two hours in the air where an infected person coughed or sneezed. Infected individuals are contagious for a couple of days before the symptoms appear.
About 1 to 2 weeks after infection, measles causes symptoms such as:
- A high fever
- Dry cough
- Red eyes
- Light sensitivity
- Runny nose
- Sore throat
- Tiny white spots inside the mouth
- A typical rash that starts on the face and spreads down the body to the trunk and legs
Most people recover within a couple of weeks, but up to 20% develop complications that may include an ear infection, bronchitis, pneumonia, diarrhea, or more rarely encephalitis or blindness. Although it is rare, one to two people, usually babies or young children, out of every thousand people infected, will die from a measles infection. People who are malnourished, have a vitamin A deficiency, or have weakened immune systems have increased risk of severe infections. Women who are pregnant when they are infected with measles are at a greater risk of miscarriage or of premature labor.
Vaccination has drastically reduced the number of people affected by measles in the United States and in many parts of the world, but the World Health Organization (WHO) still lists measles as a leading cause of death in young children. According to their estimates, measles causes about 450 deaths each day worldwide.
In 2000, endemic measles (measles continuously present in the population) was declared to be eliminated in the U.S. However, outbreaks continue to occur on an annual basis. Most cases are occurring in those people who are unvaccinated or have an unknown vaccination status, and most outbreaks are tied to travel to areas of the world where measles outbreaks are occurring.
According to the Centers for Disease Control and Prevention (CDC), in 2014, the U.S. had the highest number of measles cases reported in 20 years, with more than 600 cases. Many were linked to travelers who had visited the Philippines, where an exceptionally large outbreak of more than 50,000 cases occurred. Current CDC estimates for 2018 are 372 cases from 17 outbreaks, and for January to mid-March 2019 are 268 cases from six outbreaks. According to WHO, in 2018 there were 41,000 children and adults in Europe infected with measles in the first six months of that year. This estimate was much higher than any of the 12-month totals reported in Europe from 2000-2017.
The CDC and the U.S. and global medical communities remain concerned and vigilant. Measles is still common in many areas of the world, there is always the risk of travelers spreading measles, and there continue to be some unvaccinated individuals (including children too young for vaccination).
Mumps is a contagious viral infection that is easily spread through coughing, sneezing, talking, or by sharing items or touching surfaces with respiratory droplets or saliva on them (e.g. cups, utensils). About 2 to 3 weeks after infection you typically develop flu-like symptoms such as:
- Muscle aches
- Followed by typical parotitis – swelling of the salivary (parotid) glands below one or both ears
For most people, mumps is a mild, self-limited illness, but some may develop complications such as temporary or permanent deafness, inflammation of the testicles (orchitis) or ovaries (oophoritis), pancreatitis, meningitis, or encephalitis.
Mumps, a milder illness than measles, is much less widespread than it used to be but is still common in many parts of the world. According to the CDC, mumps cases in the U.S. range from about 200 to 2,000 a year. In the first two months of 2019, for instance, there were 151 cases of mumps reported to the CDC from 30 states and the District of Columbia.Outbreaks can occur in environments where people come in close contact, such as classrooms, sports teams, or in college dormitories. During 2011-2013, for example, several small outbreaks occurred on college campuses in California, Maryland, and Virginia, but their spread was very limited.
How is the sample collected for testing?
Antibody testing requires a blood sample, obtained by inserting a needle into a vein. Viral molecular testing may be performed on a variety of samples, including nasopharyngeal (nasal) aspirate/washing, throat swab or a swab of the inside of the cheek (buccal swab).
A nasopharyngeal swab is collected by having a person tip their head back and then a Dacron swab (like a long Q-tip with a small head) is gently inserted into one of their nostrils until resistance is met. It is left in place for several seconds, then rotated several times to collect cells, and withdrawn. This is not painful, but it may tickle a bit and cause your eyes to tear. For a nasal aspirate, a syringe is used to push a small amount of sterile saline into the nose and then gentle suction is applied to collect the resulting fluid.
In order to fully evaluate a suspected measles case, the CDC recommends the collection of blood as well as samples for RT-PCR testing. For mumps, the CDC recommends the collection of blood and a buccal swab.
Is any test preparation needed to ensure the quality of the sample?
Prior to collection of a buccal swab for mumps, the salivary gland located in front of and below the ear (parotid gland) is massaged. For other specimens, no test preparation is needed.
How is the test used?
Measles and mumps tests may be used to:
- Confirm that you are immune to the viruses due to previous infections or vaccination
- Diagnose an active case of measles or mumps
- Detect, monitor, and track outbreaks for public health purposes
A few different methods are available to test for measles or mumps:
Antibody testing (serology)
Antibody testing detects the antibodies produced by the immune system in response to a measles or mumps infection or vaccine. This testing may be used to determine whether you are immune, diagnose an active case, or to track outbreaks. There are two classes of antibodies produced:
- Immunoglobulin M (IgM) is the first type of antibody produced after infection or vaccination. The IgM antibody level (titer) increases for several days, peaks, and then begin to taper off over the next few weeks.
- Immunoglobulin G (IgG) is produced later, but once they develoo, they remain in the body for life, providing protection against re-infection. Sometimes, two blood samples are collected several days apart (acute and convalescent samples) and the level of antibodies is measured and compared. This may help to differentiate between an active infection and a prior infection.
Direct detection of the virus
Molecular methods such as PCR may be used to detect the measles or mumps virus directly in a sample. These methods only identify active infections and cannot confirm immunity.
Viral genetic testing (RT-PCR) detects and identifies the genetic strain of the virus. Most RT-PCR testing is performed by public health laboratories and the Centers for Disease Control and Prevention (CDC).
Viral detection testing may occasionally be performed to identify the cause of severe complications that may be associated with an infection from the measles or mumps virus. Since people with weakened immune systems may not have a typical antibody response, a test to detect viral genetic material may be performed to confirm the diagnosis of a mumps or measles infection, especially if antibody results do not match clinical findings or a health practitioner’s suspicions.
When is it ordered?
An IgG antibody test for measles or mumps may be ordered when your health practitioner wants to determine whether you are immune to one or both of the viruses, either because of a previous infection or due to vaccination.
Measles or mumps IgM and IgG antibody tests or PCR may be ordered when you have typical signs and symptoms of measles or mumps or when you have had contact with an infected individual and now have symptoms that could be due to measles or mumps.
Signs and symptoms of measles develop about 7 to 18 days after infection and usually include one or more of the following:
- A characteristic rash that usually starts on the face and spreads down the body to the trunk and legs
- High fever
- Dry cough
- Red, watery, itchy eyes
- Sensitivity to light
- A runny nose
- Sore throat
- Tiny white spots inside the mouth
Signs and symptoms of mumps typically develop about 2 to 3 weeks after infection and often resemble symptoms of the flu, such as:
- Muscle aches
- These are followed by characteristic swelling of the salivary glands below one or both ears called parotitis.
Testing may also be ordered during a suspected or confirmed outbreak, when several people may have been in contact with an infected person and are unvaccinated or have the signs and symptoms listed above.
What does the test result mean?
A positive IgM antibody test in someone who has not been recently vaccinated means it is likely that the person has a current measles or mumps infection. Positive IgM and IgG antibody tests or a fourfold increase in IgG levels (titers) in blood samples collected several days apart means it is likely that the person has a current or had a recent measles or mumps infection.
When measles or mumps IgG antibodies are present in a person who has been vaccinated and/or is not currently ill, then that person is protected against infection (immune). If a person does not have measles or mumps IgG antibodies, then that person is not considered immune to the viruses.
The following table summarizes results that may be seen with antibody testing:
|Positive||Positive (with an increase in levels in blood samples collected several days apart; this would only be done if the IgM test is not available)||Current or recent infection|
|Negative||Positive||Immunity from prior infection or vaccination|
|Negative||Negative||No current or prior infection; not immune; no or low immune response due to compromised immune system|
A positive measles or mumps PCR test for the virus’s genetic material means that you have a current viral infection.
If a specific strain of measles or mumps virus is identified, then this genetic strain is the cause of the infection and the genetic information can be used to help determine the source of a measles or mumps infection, such as recent travel to a specific country or recent exposure to another person with an active infection. The result of measles or mumps genetic testing is used by the Centers for Disease Control and Prevention (CDC) to monitor the spread of the virus, to identify cases that are part of outbreaks, and prevent further spread.
If the measles or mumps PCR test is negative, it may mean that you are not infected and signs and symptoms are due to another cause. However, a negative result does not necessarily rule out an active infection because the virus may have been present in numbers too low to detect or may not have been present in the sample tested. If an infection is strongly suspected after a negative result, repeat or follow-up testing may be done.
If I have measles or mumps and develop complications, will they go away once the infection resolves?
In most cases they will, but some complications, such as blindness, deafness, and rarely tissue or organ damage, may be permanent. The swelling of testicles (orchitis) that is sometimes seen with mumps can occasionally cause infertility.
When do people typically get measles and mumps vaccinations?
Two doses of the MMR vaccine are needed for full protection. Children are given the first dose of MMR vaccine between 12 and 15 months of age and a booster immunization is typically given before the start of kindergarten between 4 and 6 years of age.
The measles, mumps, rubella (MMR) vaccine contains a live, attenuated (weakened) form of the viruses. Those with weakened immune systems and women who are pregnant or planning to become pregnant within the next month should not receive the vaccine. The initial dose of the vaccine is recommended for infants at 12-15 months of age and a second dose is given at 4-6 years of age.
Should everyone be tested for measles and mumps immunity?
A test to document antibody response to the MMR vaccine is not recommended since most people produce an antibody response to the viruses in the vaccine. There are several common situations, such as entry to a university or employment in a health care setting, where you may need to provide proof that you have had the measles and mumps infections, or that you have had two MMR vaccinations, or that you have immunity to measles and mumps infection.
Is there anything else I should know?
Viral cultures for measles and mumps are not routinely available but may occasionally be done on samples such as a nasopharyngeal aspirate or washing, throat swab, cerebrospinal fluid (CSF), or urine, to help make a diagnosis.